vtkCommand Class Reference

#include <vtkCommand.h>

Inheritance diagram for vtkCommand:

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Collaboration diagram for vtkCommand:

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List of all members.


Detailed Description

superclass for callback/observer methods

vtkCommand is an implementation of the observer/command design pattern. In this design pattern, any instance of vtkObject can be "observed" for any events it might invoke. For example, vtkRenderer invokes a StartEvent as it begins to render and a EndEvent when it finishes rendering. Filters (subclasses of vtkProcessObject) invoke StartEvent, ProgressEvent, and EndEvent as the filter processes data. Observers of events are added with the AddObserver() method found in vtkObject. AddObserver(), besides requiring an event id or name, also takes an instance of vtkCommand (or a subclasses). Note that vtkCommand is meant to be subclassed, so that you can package the information necessary to support your callback.

Event processing can be organized in priority lists, so it is possible to truncate the processing of a particular event by setting the AbortFlag variable. The priority is set using the AddObserver() method. By default the priority is 0, events of the same priority are processed in last-in-first-processed order. The ordering/aborting of events is important for things like 3D widgets, which handle an event if the widget is selected (and then aborting further processing of that event). Otherwise. the event is passed along for further processing.

When an instance of vtkObject invokes an event, it also passes an optional void pointer to a callData. This callData is NULL most of the time. The callData is not specific to a type of event but specific to a type of vtkObject invoking a specific event. For instance, vtkCommand::PickEvent is invoked by vtkProp with a NULL callData but is invoked by vtkInteractorStyleImage with a pointer to the vtkInteractorStyleImage object itself.

Here is the list of events that may be invoked with a none NULL callData.

See also:
vtkObject vtkCallbackCommand vtkOldStyleCallbackCommand vtkInteractorObserver vtk3DWidget

Definition at line 198 of file vtkCommand.h.


Public Types

enum  EventIds {
  NoEvent = 0, AnyEvent, DeleteEvent, StartEvent,
  EndEvent, RenderEvent, ProgressEvent, PickEvent,
  StartPickEvent, EndPickEvent, AbortCheckEvent, ExitEvent,
  LeftButtonPressEvent, LeftButtonReleaseEvent, MiddleButtonPressEvent, MiddleButtonReleaseEvent,
  RightButtonPressEvent, RightButtonReleaseEvent, EnterEvent, LeaveEvent,
  KeyPressEvent, KeyReleaseEvent, CharEvent, ExposeEvent,
  ConfigureEvent, TimerEvent, MouseMoveEvent, MouseWheelForwardEvent,
  MouseWheelBackwardEvent, ResetCameraEvent, ResetCameraClippingRangeEvent, ModifiedEvent,
  WindowLevelEvent, StartWindowLevelEvent, EndWindowLevelEvent, ResetWindowLevelEvent,
  SetOutputEvent, ErrorEvent, WarningEvent, StartInteractionEvent,
  InteractionEvent, EndInteractionEvent, EnableEvent, DisableEvent,
  CreateTimerEvent, DestroyTimerEvent, PlacePointEvent, PlaceWidgetEvent,
  CursorChangedEvent, ExecuteInformationEvent, RenderWindowMessageEvent, WrongTagEvent,
  StartAnimationCueEvent, AnimationCueTickEvent, EndAnimationCueEvent, VolumeMapperRenderEndEvent,
  VolumeMapperRenderProgressEvent, VolumeMapperRenderStartEvent, VolumeMapperComputeGradientsEndEvent, VolumeMapperComputeGradientsProgressEvent,
  VolumeMapperComputeGradientsStartEvent, WidgetModifiedEvent, WidgetValueChangedEvent, WidgetActivateEvent,
  ConnectionCreatedEvent, ConnectionClosedEvent, DomainModifiedEvent, PropertyModifiedEvent,
  UpdateEvent, RegisterEvent, UnRegisterEvent, UpdateInformationEvent,
  SelectionChangedEvent, UpdatePropertyEvent, UserEvent = 1000
}

Public Member Functions

void UnRegister ()
virtual void UnRegister (vtkObjectBase *)
virtual void Execute (vtkObject *caller, unsigned long eventId, void *callData)=0
void SetAbortFlag (int f)
int GetAbortFlag ()
void AbortFlagOn ()
void AbortFlagOff ()
void SetPassiveObserver (int f)
int GetPassiveObserver ()
void PassiveObserverOn ()
void PassiveObserverOff ()

Static Public Member Functions

static const char * GetStringFromEventId (unsigned long event)
static unsigned long GetEventIdFromString (const char *event)

Protected Member Functions

 vtkCommand ()
virtual ~vtkCommand ()
 vtkCommand (const vtkCommand &c)
void operator= (const vtkCommand &)

Protected Attributes

int AbortFlag
int PassiveObserver

Friends

class vtkSubjectHelper

Member Enumeration Documentation

All the currently defined events are listed here. Developers can use -- vtkCommand::UserEvent + int to specify their own event ids. If this list is adjusted, be sure to adjust vtkCommandEventStrings in vtkCommand.cxx to match.

Enumerator:
NoEvent 
AnyEvent 
DeleteEvent 
StartEvent 
EndEvent 
RenderEvent 
ProgressEvent 
PickEvent 
StartPickEvent 
EndPickEvent 
AbortCheckEvent 
ExitEvent 
LeftButtonPressEvent 
LeftButtonReleaseEvent 
MiddleButtonPressEvent 
MiddleButtonReleaseEvent 
RightButtonPressEvent 
RightButtonReleaseEvent 
EnterEvent 
LeaveEvent 
KeyPressEvent 
KeyReleaseEvent 
CharEvent 
ExposeEvent 
ConfigureEvent 
TimerEvent 
MouseMoveEvent 
MouseWheelForwardEvent 
MouseWheelBackwardEvent 
ResetCameraEvent 
ResetCameraClippingRangeEvent 
ModifiedEvent 
WindowLevelEvent 
StartWindowLevelEvent 
EndWindowLevelEvent 
ResetWindowLevelEvent 
SetOutputEvent 
ErrorEvent 
WarningEvent 
StartInteractionEvent 
InteractionEvent 
EndInteractionEvent 
EnableEvent 
DisableEvent 
CreateTimerEvent 
DestroyTimerEvent 
PlacePointEvent 
PlaceWidgetEvent 
CursorChangedEvent 
ExecuteInformationEvent 
RenderWindowMessageEvent 
WrongTagEvent 
StartAnimationCueEvent 
AnimationCueTickEvent 
EndAnimationCueEvent 
VolumeMapperRenderEndEvent 
VolumeMapperRenderProgressEvent 
VolumeMapperRenderStartEvent 
VolumeMapperComputeGradientsEndEvent 
VolumeMapperComputeGradientsProgressEvent 
VolumeMapperComputeGradientsStartEvent 
WidgetModifiedEvent 
WidgetValueChangedEvent 
WidgetActivateEvent 
ConnectionCreatedEvent 
ConnectionClosedEvent 
DomainModifiedEvent 
PropertyModifiedEvent 
UpdateEvent 
RegisterEvent 
UnRegisterEvent 
UpdateInformationEvent 
SelectionChangedEvent 
UpdatePropertyEvent 
UserEvent 

Definition at line 265 of file vtkCommand.h.


Constructor & Destructor Documentation

vtkCommand::vtkCommand (  )  [protected]

virtual vtkCommand::~vtkCommand (  )  [inline, protected, virtual]

Definition at line 350 of file vtkCommand.h.

vtkCommand::vtkCommand ( const vtkCommand c  )  [inline, protected]

Definition at line 354 of file vtkCommand.h.


Member Function Documentation

void vtkCommand::UnRegister (  ) 

Decrease the reference count (release by another object). This has the same effect as invoking Delete() (i.e., it reduces the reference count by 1).

virtual void vtkCommand::UnRegister ( vtkObjectBase  )  [inline, virtual]

Decrease the reference count (release by another object). This has the same effect as invoking Delete() (i.e., it reduces the reference count by 1).

Reimplemented from vtkObjectBase.

Definition at line 206 of file vtkCommand.h.

virtual void vtkCommand::Execute ( vtkObject caller,
unsigned long  eventId,
void *  callData 
) [pure virtual]

All derived classes of vtkCommand must implement this method. This is the method that actually does the work of the callback. The caller argument is the object invoking the event, the eventId parameter is the id of the event, and callData parameter is data that can be passed into the execute method. (Note: vtkObject::InvokeEvent() takes two parameters: the event id (or name) and call data. Typically call data is NULL, but the user can package data and pass it this way. Alternatively, a derived class of vtkCommand can be used to pass data.)

Implemented in vtkCallbackCommand, vtkEventForwarderCommand, and vtkOldStyleCallbackCommand.

static const char* vtkCommand::GetStringFromEventId ( unsigned long  event  )  [static]

Convenience methods for translating between event names and event ids.

static unsigned long vtkCommand::GetEventIdFromString ( const char *  event  )  [static]

Convenience methods for translating between event names and event ids.

void vtkCommand::SetAbortFlag ( int  f  )  [inline]

Set/Get the abort flag. If this is set to true no further commands are executed.

Definition at line 234 of file vtkCommand.h.

int vtkCommand::GetAbortFlag (  )  [inline]

Set/Get the abort flag. If this is set to true no further commands are executed.

Definition at line 236 of file vtkCommand.h.

void vtkCommand::AbortFlagOn (  )  [inline]

Set/Get the abort flag. If this is set to true no further commands are executed.

Definition at line 238 of file vtkCommand.h.

void vtkCommand::AbortFlagOff (  )  [inline]

Set/Get the abort flag. If this is set to true no further commands are executed.

Definition at line 240 of file vtkCommand.h.

void vtkCommand::SetPassiveObserver ( int  f  )  [inline]

Set/Get the passive observer flag. If this is set to true, this indicates that this command does not change the state of the system in any way. Passive observers are processed first, and are not called even when another command has focus.

Definition at line 249 of file vtkCommand.h.

int vtkCommand::GetPassiveObserver (  )  [inline]

Set/Get the passive observer flag. If this is set to true, this indicates that this command does not change the state of the system in any way. Passive observers are processed first, and are not called even when another command has focus.

Definition at line 251 of file vtkCommand.h.

void vtkCommand::PassiveObserverOn (  )  [inline]

Set/Get the passive observer flag. If this is set to true, this indicates that this command does not change the state of the system in any way. Passive observers are processed first, and are not called even when another command has focus.

Definition at line 253 of file vtkCommand.h.

void vtkCommand::PassiveObserverOff (  )  [inline]

Set/Get the passive observer flag. If this is set to true, this indicates that this command does not change the state of the system in any way. Passive observers are processed first, and are not called even when another command has focus.

Definition at line 255 of file vtkCommand.h.

void vtkCommand::operator= ( const vtkCommand  )  [inline, protected]

Definition at line 355 of file vtkCommand.h.


Friends And Related Function Documentation

friend class vtkSubjectHelper [friend]

Definition at line 352 of file vtkCommand.h.


Member Data Documentation

int vtkCommand::AbortFlag [protected]

Definition at line 346 of file vtkCommand.h.

int vtkCommand::PassiveObserver [protected]

Definition at line 347 of file vtkCommand.h.


The documentation for this class was generated from the following file:

Generated on Sat Dec 27 13:20:26 2008 for VTK by  doxygen 1.5.6